372 PARASITES OF ANIMALS 



horses. The palsy of the bowel which arises in this way may 

 explain also the frequent ruptures of the digestive canal and 

 the greater number of its changes in position. The latter are 

 specially favored by the structure of the abdominal viscera in 

 the horse. 



15. The old changes which one finds in the peripheral 

 branches of the anterior mesenteric artery, in the form of 

 expired and partly absorbed embolic and thrombolic processes 

 (pigmentation, arterial and venous thrombi), particularly in 

 connection with those arteries which are seats of the aneurism, 

 decisively prove that the large majority of colics resulting in 

 recovery, so far as they do not depend upon known injuries, 

 are caused by paralysis of the bowel from embolism and 

 thrombosis. The sudden occurrence, course, and result of these 

 kinds of colics also testify to their embolic origin. 



16. The oedematous, inflammatory, and hsemorrhagic pro- 

 cesses that one often finds described as the cause of death in colic, 

 almost exclusively depend on thrombosis and embolism of the 

 mesenteric arteries, the cases forming about 40 to 50 per cent, 

 of all fatal colics. 



17. The rapid course in fatal colics, as well as the prepon- 

 derating symptoms of dyspnoea in cases of recovery, is finally 

 due to the abnormal development of gas in the alimentary 

 canal. In addition to the diminution of the respiratory surface 

 by the lofty position of the diaphragm, a direct gas-poisoning 

 (carbonic acid and sulphuretted hydrogen) probably contributes 

 to the intensity of the symptoms and the rapid course by 

 diffusion of the abnormally developed gas out of the intestinal 

 canal into the blood. 



18. The variety of the anatomical derangements caused by 

 embolism and thrombosis of the intestinal arteries is faithfully 

 mirrored by the variety of the clinical symptoms and the 

 different degrees in the intensity and course of the colic. 



19. Amongst every 100 horses afflicted with internal disease, 

 40 are ill with colic. Among any hundred deceased horses 40 

 have perished from colic, and among 100 colic patients 87 

 recover and 13 die. The figures prove that neither amongst 

 the epizootic nor sporadic diseases of horses is there any other 

 affection which occurs so frequently, or claims anything like so 

 many victims. Like the frequency of the worm-aneurism, the 

 amount of disease and mortality increases with advancing age. 

 The etiology of the colic of horses finds in the thrombosis and 



